As Terry suggest, it all reads like burned out heating elements. What cannot be explained is why there was no hot water to begin with. I'm leaning that the red button on the thermostat tripped and it was not realized? I had a lightning storm trip one out on me.
If you need to buy a meter, do get a clamp meter. It will also allow you to check current draw. HD and Lowes have one between $50-$60 for a basic unit. Harbor Freight less than that.
For electric residential water heaters all thermostats work identical. Using a meter to test is a bit tricky of you do not know how to use one. With power on at L1 & L3 (others might be tables at L2), 240 volts would be present. at L4 and the non labeled screw terminal above T2 should also read 240 volts. If not press the red button to reset the breaker.
Turn off power completely and disconnect the wire at T2, With the meter on the Ohm scale measure the resistance across the
heating element. It should read about 12-13 ohms. If no reading, it burned open. Check the lower element also by removing one wire. Note, with power on with burned out elements or good ones, you'll read 240 volts on the top one. Zero on the lower one since the upper thermostat is not at the set temperature to switch power to the lower one.
With good heating elements, tank filled with water, using the clamp meter you'll read about 18 amps of current draw when the element is powered on. Place the clamp on L1 or L3 or a wire to the heating element.